In 1943, Heinrich Himmler, leader of the SS and an all-around monster, decided it would be a good idea to take the top members of France’s political and cultural elite and imprison them in a medieval castle in Austria. That sentence alone should tell you that the Nazis’ predilection for acts of Hollywood villainy was deep-seated and incurable. But real events soon became stranger than fiction. A small American recon platoon managed to liberate the captives during the closing days of the war, and fought a desperate last stand to prevent their SS captors from returning.

Fighting alongside the small American force against the Waffen SS were more than a dozen Wehrmacht (Army) soldiers—making the Battle at Itter Castle possibly the only engagement in which U.S. and German troops fought on the same side in World War II.

This unique conflict has been most thoroughly documented in The Last Battle by Stephen Harding, whose book has since been optioned as a movie—and inspired a heavy-metal music video. Harding’s work particularly focuses on the fourteen French notables stuck in the castle, which included both French prime ministers at the start of World War II, Édouard Daladier and Paul Reynaud, and top military commanders Maxime Weygand and Maurice Gamelin. For a good measure they also threw in Marie-Agnès Cailliau, the sister of the current leader of the Free French; Michel Clemenceau, son of the French leader during World War I; and French tennis star Jean Borotra—because, well, why not? There were also several wives and one husband who elected to join their partners in the prison.

This forced reunion of French VIPs, many of whom passionately hated each other, included both Vichy collaborators, such as Borotra and Weygand, and members of the Resistance, some of them transferred there from concentration camps. It had the making of a grotesque hostage situation—or, the captives feared, a soon-infamous massacre.

Itter Castle, actually a nineteenth-century construction built upon the site of a thirteenth-century century fortress, was situated atop a nearly seven-hundred-meter-high hill just a few miles south of the town of Wörgl. Seized by Himmler in 1943, it was administratively attached to the Dachau concentration camp, which contributed a staff of eastern European prisoners to serve as the prison’s staff.

However, it doesn’t seem Himmler ever attempted to leverage the captives in Castle Itter to his political advantage, and the American troops advancing into Austria in May 1945 had no idea of its significance. Indeed, even the prison’s commandant, Sebastian Wimmer, ran away from his charges on May 4, promptly followed by the rest of the guards. The liberated prisoners snatched up the small arms that had left behind and even enlisted a wounded SS officer, Kurt Schrader, to help protect them. However, they were still surrounded by hostile SS troops. Though the imprisoned Croatian resistance fighter Zvonimir Cuckovic managed to slip away on the pretense of running an errand and contact U.S. troops on May 3, an attempted rescue effort was aborted in the face of German shellfire and concerns about intruding into a neighboring American unit’s operating area (truly!).

On May 4, the castle’s Czech cook, Andreas Krobot, rode away on bicycle in a second attempt to find help. He finally encountered the unit of Maj. Josef Gangl in the town of Wörgl. The Austrian major had commanded howitzers on the Eastern Front and Nebelwerfer rocket launchers in the Battle of Normandy. Ordered to make a last stand against the advancing U.S. Twelfth Armored Division, he had instead contacted the local Austrian resistance under Alois Mayr, providing them with weapons and agreeing that they needed to prevent a destructive battle on Austrian soil at all costs. The SS had orders to shoot Austrians who showed signs of welcoming the incoming Allies, and Gangl’s troops were ready to fight back—but he hoped that American troops would arrive before that was necessary. After speaking with Krobot, Gangl agreed to dispatch his small force to protect the prisoners in Itter in case the SS tried to take it back.

On the way, Gangl’s troops—embarked on a Kübelwagen command car and a truck—encountered a reconnaissance unit from the Twenty-Third Armored Battalion in the village of Kufstein, operating well in advance of its parent formation. Commanding the unit’s four running Sherman tanks was First Lieutenant John “Jack” Lee. Gangl raised a white flag and explained the situation at Castle Itter. The New Yorker decided to help out—and they headed down to Itter together, overcoming a bridge wired to explode along the way, and scattering SS troops setting up a machine-gun nest.

The liberation force was eventually pared down to only fourteen Germans and ten Americans, as the other tanks were left behind to man roadblocks. This left only Jack’s tank Besotten Jenny, an upgraded “Easy 8” Sherman tank named with a high-velocity seventy-six-millimeter gun, with several African American soldiers from the Seventeenth Armored Infantry Battalion riding on top.

The French prisoners were unimpressed by the rescue party—Reynaud later wrote that Lee was “crude in both looks and manners.” Nonetheless, Lee quickly deployed his handful of troops and the armed French captives into defensive positions, and positioned Besotten Jenny in front of the gatehouse.

This was fortunate, as troops from the nearby Seventeenth SS Panzergrenadier (Armored Infantry) Division soon began moving against the castle. That night, an SS infantry force raked Castle Itter’s walls with rifle and machine gun fire, but the defenders beat them back with their own small arms. By the following morning, around 150 to two hundred SS troops had massed to besiege Castle Itter, setting up a deadly eighty-eight-millimeter antitank gun and a twenty-millimeter flak gun on a hill eight hundred yards away. Meanwhile, just two additional members of the Austrian resistance arrived to reinforce the castle’s defenders.

The SS artillery began systematically blasting apart the crenellations and windows the castle’s defenders were shooting from. An antitank round blew through the side hull of Besotten Jenny, with the crew barely escaping before the tank brewed up in flames. The SS infantry then stormed towards the castle, despite taking losses to the defenders—which included both of the aged French former prime ministers and the seventy-year-old Michel Clemenceau! The tennis star Borotra volunteered to run the SS lines to look for help. He jumped the wall, dashed across forty meters of open ground, evaded the encircling SS troops in the woods and eventually linked up with American soldiers of the 142nd Regimental Combat Team.

But the SS attackers continued to advance. Several of the German defenders of Castle Itter were killed, including Major Gangl, mortally wounded by a sniper’s bullet. By the afternoon, a German antitank team was coming into position to blow up the fortress’s main gate with Panzerfaust rockets.

Suddenly, cannon fire rang from behind the German attackers—Jenny’s sister tank Boche Buster, accompanied by a company of American infantry, was riding into the rescue. They were later joined by troops from the 142nd battalion, led by Borotra, sporting an American uniform. He had led in the infantry of G Company supported by a tank platoon. Along the way, they knocked out several machine-gun nests, and narrowly dodged an ambush by a self-propelled seventy-five-millimeter gun on a German 251/22 halftrack before destroying it with a seventy-six-millimeter shell.

The relief forces captured over a hundred SS prisoners. By that evening, the French prisoners were being driven to Paris. Nazi Germany surrendered three days later on May 8.

In all honesty, it’s not clear whether the SS troops were actually under orders to deliberately massacre the French elites, as has been alleged. However, it would have been very bad if they had, intentionally or in the heat of battle, as the French Republic was in the painful process of reconstituting itself. Following the war, both Reynaud and Daladier would go on to hold political office.

What’s striking about the battle at Itter is how the German, American, French and eastern European defenders of the castle acted on their own initiative to salvage the situation, rather than at the behest of higher commanders. Of course, it’s hard to know precisely what motivated Gangl and his followers to finally turn against the excesses of an evil regime in its final hours. Regardless, France can be thankful that the German major went out of his way to do the right thing, making the ultimate sacrifice protecting both French leaders and his fellow Austrians.

Sébastien Roblin holds a master’s degree in conflict resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing and refugee resettlement in France and the United States. He currently writes on security and military history forWar Is Boring.